Smug Git
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Registered: Aug 2001
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Nearby 'earthlike' planets?
Story
quote:
Dusty disc may mean other Earths
By Dr David Whitehouse
BBC News Online science editor
Astronomers say they have evidence for Earth-like planets orbiting a nearby star, making it more like our own Solar System than any yet discovered.
The star, Vega, is one of the brightest in the sky, only 25 light years away.
It is three times larger than our Sun and, at 350 million years old, much younger as well.
Vega has a disc of dust circling it, and at least one large planet which could sweep debris aside allowing smaller worlds like Earth to exist.
The analysis, by astronomers from the Royal Observatory, Edinburgh, is published in The Astrophysical Journal, and is based on observations taken with one of the world's most sensitive cameras.
The device, the Submillimetre Common-User Bolometer Array (Scuba), is attached to the James Clerk Maxwell radio telescope in Hawaii.
Computer model
Its detailed images of Vega and its environment confirm the presence of a disc of very cold dust (-180C) in orbit around the star.
New computer modelling techniques show that structure seen in the disc can be best explained by a Neptune-like planet orbiting at a similar distance to Neptune in our own Solar System and having similar mass.
The disc contains a Neptune-like planet
The wide orbit of the Neptune-like planet means that there is plenty of room inside it for small rocky planets similar to the Earth.
"The shape of the disc is the clue that it is likely to contain planets," says Mark Wyatt of the Royal Observatory, Edinburgh.
"Although we can't directly observe the planets, they have created clumps in the disc of dust around the star."
If this is the case then it may mean that Vega has a planetary system like our own.
Subject to test
The Vega system may have evolved a similar way to our Solar System with gas giants such as Neptune forming close to the Sun, and then being pushed out to their current orbits by gravitational interactions with their neighbours.
During this process such giant planets suck in all the debris that would otherwise pound young planets, allowing life to develop more easily upon them.
The idea can be tested in two ways as Wayne Holland, who made the original observations, explains: "The model predicts that the clumps in the disc will rotate around the star once every 300 years.
"If we take more observations after a gap of a few years we should see the movement of the clumps.
"Also the model predicts the finer detail of the disc's clumpiness which can be confirmed using the next generation of telescopes and cameras."
What is cool about this, I think, is that it might give us some more insight into how our own solar system formed (and allow us to test some of our existing theories on that subject). The fact that it is close means that we can actually observe it relatively well, too. I guess that that will then allow us some more insight into how much of a fluke the coincidence of factors that gave rise to the situation on earth in which life could evolve is (although it won't tell us about other configurations which might also support life in a different way).
Anyone who goes on enthusiastically about the Drake equation should, of course, be banned.
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12-01-2003 09:38 AM
